Biological pathways represent knowledge about molecules, processes and their interactions, the cellular wiring diagram. Researchers use pathway maps to design and analyze experiments and to make predictions about the behavior of biological systems. Pathway information is, unfortunately, extremely difficult for biologists to use in its current fragmented and incomplete state. We plan to overcome this roadblock to biological research by developing the Pathway Commons Research Resource. Pathway Commons benefits researchers as a convenient single point of access to diverse biological pathway information translated to a common data language (www.pathwaycommons.org). To provide this service, we will aggregate datasets from many existing pathway databases;translate, store, validate, index, integrate, hyperlink and maintain the information for maximum quality access;freely distribute pathway information to the scientific public, both academic and commercial;and, provide open-source end user software for pathway browsing and analysis. Pathway Commons promotes and supports convergence, by the community, to a truly integrated representation of cellular biological processes. Using Pathway Commons, biology research groups will be able to quickly find and analyze information about cellular biological processes. Primary database 'groups will be able to share their pathway data, thus increase access, reduce software development and curation costs and avoid duplication of effort. Bioinformatics software developers will be able to increase efficiency by sharing open-source software components. The completion of the human genome sequence and advances in molecular technologies are driving biology towards increased use of computational tools. Pathway Commons will make biological knowledge available for computational processing and help create predictive computational models of biological processes, which will revolutionize many areas of biology, including health research.